Remove any mention on X/Twitter from main website. (#780)

Co-authored-by: Simon Li <orpheus+devel@gmail.com>

Author: Carreau

_includes/biocard.html

@@ -26,9 +26,6 @@
       {% if include.mastodon %}
         <a href="{{ include.mastodon }}" rel="noopener noreferrer"><img src="/assets/badges/mastodon.svg" alt="Mastodon" title="Mastodon"></a>
       {% endif %}
-      {% if include.twitter_handle %}
-        <a href="https://twitter.com/{{ include.twitter_handle }}" rel="noopener noreferrer"><img src="/assets/badges/twitter.svg" alt="Twitter" title="Twitter"></a>
-      {% endif %}
       {% if include.subproject %}
         <div class="biocard-subproject">{{ include.subproject }}</div>
       {% endif %}

_layouts/default.html

@@ -41,8 +41,8 @@
     url: https://github.com/jupyter/
   - title: Mastodon
     url: https://hachyderm.io/@ProjectJupyter
-  - title: X
-    url: https://x.com/ProjectJupyter
+  - title: BlueSky
+    url: https://bsky.app/profile/projectjupyter.bsky.social
   - title: YouTube
     url: https://www.youtube.com/@projectjupyter
 legal:

social.md

@@ -26,11 +26,11 @@ List of channels actively maintained by JMS in alphabetical order:
 - Medium: https://blog.jupyter.org
 - Mastodon:  https://hachyderm.io/@ProjectJupyter
 - Slack JupyterLab: https://jupyterlabworkspace.slack.com
-- X/Twitter Jupyter: https://twitter.com/ProjectJupyter
 - YouTube: https://youtube.com/@projectjupyter
+- BlueSky : https://bsky.app/profile/projectjupyter.bsky.social
+
 
 List of channels considered inactive but managed by the JMS:
 
 - Facebook: https://facebook.com/projectjupyter
 - Slack JupyterCon 2023: https://jupyterconworkspace.slack.com
-- X/Twitter JupyterCon: https://twitter.com/JupyterCon